Speaking for myself, I know I've considered it because I am not always pleased with the kids' school. From an academic standpoint and in general. The main thing stopping me from giving it a try is my lack discipline. I don't feel confident that I could do a good job and this is not the kind of thing that you can risk easily.
@NettieNettie, I have the same issues even though we are in the thick of it. I know I can do at least as good a job as their public school did, kwim? But it did require a huge mental leap from thinking about homeschooling to actually becoming homeschoolers.